[DAGCombiner] Try to use SelectionDAG::isKnownToBeAPowerOfTwo instead of just APInt::isPowerOf2
Generalize sdiv/udiv/srem/urem combines using APInt::isPowerOf2, which only works for const/splat-const values, to call SelectionDAG::isKnownToBeAPowerOfTwo instead which recognises many more cases.
Added a DAGCombiner::BuildLogBase2 helper since PowerOf2 combines often involve taking the log2 of such a value.
Differential Revision: https://reviews.llvm.org/D27714
llvm-svn: 289654
diff --git a/llvm/test/CodeGen/X86/combine-sdiv.ll b/llvm/test/CodeGen/X86/combine-sdiv.ll
index 3d59fb0..ddb1786 100644
--- a/llvm/test/CodeGen/X86/combine-sdiv.ll
+++ b/llvm/test/CodeGen/X86/combine-sdiv.ll
@@ -82,30 +82,33 @@
; SSE-LABEL: combine_vec_sdiv_by_pos1:
; SSE: # BB#0:
; SSE-NEXT: pand {{.*}}(%rip), %xmm0
-; SSE-NEXT: pextrd $1, %xmm0, %eax
-; SSE-NEXT: shrl $2, %eax
-; SSE-NEXT: pextrd $2, %xmm0, %ecx
-; SSE-NEXT: pextrd $3, %xmm0, %edx
-; SSE-NEXT: pinsrd $1, %eax, %xmm0
-; SSE-NEXT: shrl $3, %ecx
-; SSE-NEXT: pinsrd $2, %ecx, %xmm0
-; SSE-NEXT: shrl $4, %edx
-; SSE-NEXT: pinsrd $3, %edx, %xmm0
+; SSE-NEXT: movdqa %xmm0, %xmm2
+; SSE-NEXT: movdqa %xmm0, %xmm1
+; SSE-NEXT: psrld $3, %xmm1
+; SSE-NEXT: pblendw {{.*#+}} xmm1 = xmm0[0,1,2,3],xmm1[4,5,6,7]
+; SSE-NEXT: psrld $4, %xmm0
+; SSE-NEXT: psrld $2, %xmm2
+; SSE-NEXT: pblendw {{.*#+}} xmm2 = xmm2[0,1,2,3],xmm0[4,5,6,7]
+; SSE-NEXT: pblendw {{.*#+}} xmm1 = xmm1[0,1],xmm2[2,3],xmm1[4,5],xmm2[6,7]
+; SSE-NEXT: movdqa %xmm1, %xmm0
; SSE-NEXT: retq
;
-; AVX-LABEL: combine_vec_sdiv_by_pos1:
-; AVX: # BB#0:
-; AVX-NEXT: vpand {{.*}}(%rip), %xmm0, %xmm0
-; AVX-NEXT: vpextrd $1, %xmm0, %eax
-; AVX-NEXT: shrl $2, %eax
-; AVX-NEXT: vpinsrd $1, %eax, %xmm0, %xmm1
-; AVX-NEXT: vpextrd $2, %xmm0, %eax
-; AVX-NEXT: shrl $3, %eax
-; AVX-NEXT: vpinsrd $2, %eax, %xmm1, %xmm1
-; AVX-NEXT: vpextrd $3, %xmm0, %eax
-; AVX-NEXT: shrl $4, %eax
-; AVX-NEXT: vpinsrd $3, %eax, %xmm1, %xmm0
-; AVX-NEXT: retq
+; AVX1-LABEL: combine_vec_sdiv_by_pos1:
+; AVX1: # BB#0:
+; AVX1-NEXT: vpand {{.*}}(%rip), %xmm0, %xmm0
+; AVX1-NEXT: vpsrld $4, %xmm0, %xmm1
+; AVX1-NEXT: vpsrld $2, %xmm0, %xmm2
+; AVX1-NEXT: vpblendw {{.*#+}} xmm1 = xmm2[0,1,2,3],xmm1[4,5,6,7]
+; AVX1-NEXT: vpsrld $3, %xmm0, %xmm2
+; AVX1-NEXT: vpblendw {{.*#+}} xmm0 = xmm0[0,1,2,3],xmm2[4,5,6,7]
+; AVX1-NEXT: vpblendw {{.*#+}} xmm0 = xmm0[0,1],xmm1[2,3],xmm0[4,5],xmm1[6,7]
+; AVX1-NEXT: retq
+;
+; AVX2-LABEL: combine_vec_sdiv_by_pos1:
+; AVX2: # BB#0:
+; AVX2-NEXT: vpand {{.*}}(%rip), %xmm0, %xmm0
+; AVX2-NEXT: vpsrlvd {{.*}}(%rip), %xmm0, %xmm0
+; AVX2-NEXT: retq
%1 = and <4 x i32> %x, <i32 255, i32 255, i32 255, i32 255>
%2 = sdiv <4 x i32> %1, <i32 1, i32 4, i32 8, i32 16>
ret <4 x i32> %2